Roofing-felt



UNITED STATES PATIENT OFFICE.

I ALBERT L. GLAPP, 0F MARBLEHEAD, MASSACHUSETTS, ASSIGNOR TO REGINALEBIRD, OF FRAMINGHAM, MASSACHUSETTS. v

ROOFING-FELT.

No Drawing.

and useful Improvements in Roofing-Felts,

of which the following is a specification.

This invention has relation to the art of felt-making and also relatesto the manufacture of prepared weatherproof roofing material.

In the manufacture of artificial or prepared shingles or sheet roofingthere are used certain weatherproof pitchy asphaltic bituminous orhydrocarbon compounds of such character that they will withstand solarheat and the action of the elements, when exposed on the roof or side ofa building. Various materials of this general character are used forimpregnating and for coating the roofing material. It is preferable forthe saturating compound, however, to employ those materials which have arelatively low melting point, and to use for the coating or facingmaterials having a relatively higher melting point and which are rela-,tively tough and hard. These various materials cannot be used alone, a'.e. formed in thin slabs, and consequently it is necessary to use somesort of orous foundation or support therefor. eretofore it has beencustomary to utilize for this purpose what is known as felt, whichconsists largely of rag fibers, sometimes with a small amount of woolfiber incorporated therein. Such felt of the desired thickness is firstimpregnated with the saturating compound, which may consist of alow-melting-point tar asphalt or a mixture of soft asphalts, rosins,oils, wax tailings, etc. The saturating compound is rendered molten byheat and the sheet of According to modern practice, however, it

is customary, while the exterior coating is soft and plastic, to applythereto a thick facing or layer of crushed slate, grit, or othergranular comminuted or crushed ma- Specification of Letters Patent.Patented Apr. 12, 1921. Application filed February 7, 1918. Serial No.215,891.

embedded in the soft and plastic: coating."

Ornamental effects are secured by using mineral materials of differentcolors and applying them in designs in spaced areas on the surface ofthe sheet.

The support or foundation, which serves as the medium for holding inplace the saturating Waterproofing compound and the exterior coatings orfacings, must be of such character that the molten saturating compoundmay easily penetrate it within a short space of time; In order that theroofing material may be produced at low cost, it' is necessary that thesheet of felt or the sheet forming the support should be fed through themolten bath of saturating compound at a relatively high speed, and itwill be understood by those skilled in the art that the greater thedegree to which the support is saturated, the greater will be thedurability thereof. According to the requirements of the National Boardof Underwriters, prepared roofing used for shingles or the like musthave at least a certain minimum wei ht per square foot. or support ischaracterized by slow penetrability, the saturating compound must be sosoft that it is impracticable and will, when the roofing is laid, oozefrom the roofin or else the compound must be heated to sue a de ree oftemperature as to injure the foundatlon or support as it is passingtherethrough. I

After long experimentation, I have succeeded in producing, for use as afoundation or support for roofing material, what may be termed a feltwhich is characterized by three optimum characteristics: first, it is ofsufficient strength to withstand the strains to which it is exposedduring the impregnation and coating operations; second, it has a highdegree of penetrability so that it may be saturated to a maximum extentmore rapidly than heretofore found practicable; and, third, it is ofsuch flexibility that, after being saturated and coated, it does notreadily {oreak when bent at a relatively sharp an e.

y the present invention I have succeeded in producing a felt having theoptimum characteristics, by incorporating in the felt in the manufacturethereof a quantity of sawdust, by which interstices are formed in thefabric without weakeningthe same and thereby increasing the porosity andpenetrability of the felt. The sawdust is preferably relatively fine sothat lumps are not formed on the surface of the felt, and in fact Ifrequently find it desirable to employ sawdust oftwo grades, to wit thatof soft wood, and fine sawdust of hard wood such as produced in sawingveneers, etc. Both kinds of sawdust are fibrous in character, and aremore or less permeated by the saturating compounds. If ordinary sawdustis em.- ployed it should be screened, and that portion used which willpass through a 25 to 50 mesh sieve, to secure the best results.

The sawdust and the rag fiber are placed in a beater engine andsubjected to the operation thereof until the pulp is of the properconsistency after which it is formed into a felt web or sheet accordingto the known -methods followed in making felt.

Instead of employing only rags, I preferably use a mixture of rags andpaper, such as waste newspapers. The proportion of.

.. tracting from the requisite flexibility thereof. v

In practice,"I place 60 parts by weight of rags, and 25 parts by weightof newsprintin the beating engine together with the proper quantity ofwater, and they are subjected to a beating operation for about an hour.Then about 15 parts of sawdust (half soft wood sawdust and half veryfine hard wood sawdust) are added to the beater, and the mixture beatenfor about an hour and a half, the beating operation serving to reducethe larger particles of wood, and to form a practically homogeneouspulp, z. e. with the sawdust fully distributed therethrough. The pulp isthen formed into felted sheets according to the usual methods which neednot be describedi- While, as I have stated, any relatively fine sawdustof any suitable kind may be employed, I preferably use and recommend aportion, at least, of fairly minute hard wood,

sawdust, but in any event the sawdust should not be of such large grainsas to form lumps on the surface of the, sheet, as these lumps aresubsequently rendered more prominent after the saturating and coatingprocesses to which the sheet is subjected in the manufacture of preparedroofing.

Felt formed as herein deEcribed is soft and pliable. It possesses thedesired tensile strength, and because of the presence of the particlesof sawdust, the felt is full of voids and interstices into which thesaturating compound may penetrate rapidly,'so that the signature.

sheet may be fed at relatively high speed through the saturating vat.

I find that such felt is capable of absorbing and retaining a greaterweight of saturating compound per square foot, than ordinary felt of thesame thiclmess manufactured of rag fiber, or of a mixture of rag fiberand sistant quality and to present an ornamental appearance.

What I claim is:

1. As a new article of manufacture, a flexible sheet composed of amixture of rag fiber and sawdust intimately commingled in suchproportions as toresult in a product of high penetrability and tensilestrength so as to adapt it as a foundation for prepared roofing.

2. As a new article of manufacture, a

flexible sheet composed of a mixture of rag fiber, paper stock andsawdust intimately commingled and beaten together in such proportions asto result in-a product having high penetrability and tensile strength soas to adapt it for a foundation for prepared roofing.

3. As a new article of manufacture, a

flexible sheet of high penetrability, adapted for a foundation forprepared roofing, comprising a mixture of approximately 60 parts byweight of rag fiber, 25 parts by weight of paper stock and 15 parts byweight of sawdust, all intimately commingled.

4. As a new article of manufacture, a

5. s a new article of manufacture, a

flexible sheet of high penetrability, adapted for a foundation forprepared roofing, composed of a mixture of rag fiber and sawdust, suchsawdust consisting of relatively coarse particles of soft wood andrelatively fine particles of hard wood, all intimately mixed and beatentogether.

' 6'. As a new article of manufacture, a roofing sheet composed of afoundation of felt having sawdust incorporated therein and forming voidsor interstices, and contaming 1n the pores and-interstices of the sheetand the fibers thereof, an asphaltic compound substantially as hereindescribed. In testimony whereof I have afiixed my ALBERT L. CLAPP.

